[rrd-users] dump/restore creates non-identical files with rrdtool-1.4

[Tobias Oetiker]

Hi Mike,

the difference between restored files should actually be greater
than what you describe here because rra pointer location gets
randomized ... the reason for this is that the dumped xml is always
'in sequence' this means that the data in the xml RRA sections
start with the oldest entry. If this was maintained in the binary
format, all RRAs would tend to be block-aligned which causes bursty
IO as block borders are crossed.

you should rather do dump / restore / dump to compare ...
or info / dump / restore / info

cheers
tobi




> Another (obscure) change: If you dump a rrd file and then restore it,
> with rrdtool 1.4, the new file will be no longer identical with the
> dumped database. The difference is just a couple of null bytes, so
> probably nothing to worry about, just another test case that was
> triggered (foo=original foo1=restored):
>
> *** foo.hex     2010-02-21 22:55:18.000000000 -0800
> --- foo1.hex    2010-02-21 22:55:22.000000000 -0800
> ***************
> *** 21,26 ****
>    000001d0  00 00 f8 ff 03 00 00 00  00 00 00 00 00 00 00 00  |................|
>    000001e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
>    *
>    00000220  00 00 00 00 00 00 f8 ff  00 00 00 00 00 00 f8 ff  |................|
>    *
> ! 00000270
> --- 21,28 ----
>    000001d0  00 00 f8 ff 03 00 00 00  00 00 00 00 00 00 00 00  |................|
>    000001e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
>    *
> + 00000210  00 00 00 00 00 00 00 00  00 00 00 00 06 00 00 00  |................|
>    00000220  00 00 00 00 00 00 f8 ff  00 00 00 00 00 00 f8 ff  |................|
>    *
> ! 00000270  00 00 00 00                                       |....|
> ! 00000274
>
>
> -- Mike
>
> Mike Schilli
> m at perlmeister.com
>
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>

-- 
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900